Cautious scientists are talking possible AIDS cure JUL 27 2012

AIDS patients are susceptible to cancers, but they usually stop taking HIV drugs before receiving cancer treatment. "That allows the virus to come back and it infects their donor cells," Kuritzkes said.

About 34 million people are infected with HIV, the virus that causes AIDS, globally; 25 million have died from it. While there's no vaccine, cocktails of powerful antiviral drugs called antiretroviral therapy (ART) can keep the virus suppressed and keep patients healthy. No matter how long patients take ART, however, they are never cured. The virus lurks in the body and comes back if the drugs are stopped. Scientists want to flush out these so-called reservoirs and find a way to kill the virus for good.

Brown, and now these two other men, offer some real hope.

Dr. Timothy Henrich and colleagues at Brigham and Women's Hospital launched a search about a year ago for HIV patients with leukemia or lymphoma who had received bone marrow stem cell transplants. Bone marrow is the body's source of immune system cells that HIV infects and it's a likely place to look for HIV's reservoirs.

"If you took an HIV patient getting treated for various cancers, you can check the effect on the viral reservoirs of various cancer treatments," Kuritzkes, who works with Henrich, said. They found the two patients by asking colleagues at Dana-Farber Cancer Institute in Boston which, like Brigham and Women's, is associated with Harvard Medical School.

Both men had endured multiple rounds of treatment for lymphoma, both had stem cell treatments and both had stayed on their HIV drugs throughout. "They went through the transplants on therapy," Kuritzkes said.

It turns out that was key.

"We found that immediately before the transplant and after the transplant, HIV DNA was in the cells. As the patients' cells were replaced by the donor cells, the HIV DNA disappeared," Kuritzkes said. The donor cells, it appears, killed off and replaced the infected cells. And the HIV drugs protected the donor cells while they did it.

The two men have been HIV-free for two years and three-and-a-half years, respectively. Another man who benefited from a bone marrow transplant from a donor whose immune cells resist HIV infection has been free of HIV for five years. (via @gavinpurcell)